The present application is directed to a method of controlling a conjunctivitis known as "pinkeye", in cattle and other livestock by placing a subcutaneous antibiotic implant in close proximity to each eye of an animal to be treated in accordance with the method.
Pinkeye is the common name for a conjunctivitis or inflammation of the conjunctiva. This conjunctivitis can result in ulceration of the eyeball, severe pain, blepharospasm, excess tearing and eventually corneal perforation with subsequent prolapse of the intraocular contents, blindness, weight loss and substantial decrease in value to the owner. Because of the colorization of the eyeball, the disease is commonly known as pinkeye. Various microbes may be associated with the inflammation with the most common being one or more of the strains of Moraxella Bovis.
While microbes are associated with the inflammation, there appear to be different opinions as to the exact primary and secondary causes of conjunctivitis in cattle and as to what events must occur to result in such an inflammation. Obviously, there must be some exposure to the infecting microbe.
It may also be necessary to have some exposure to ultraviolet radiation which can be provided by the sun and/or other factors including dust, weed growth, stresses that compromise the animal's defense system, and insect, especially fly, infestation. Flies also may transport and transmit the infectious bacteria between animals. Most cases of conjunctivitis in the northern hemisphere occur during what is referred to as the peak period for conjunctivitis: during the period extending from July to October. This also correlates with the period of greatest sunshine and with the greatest incidence of the other noted factors.
Conjunctivitis can lead to serious problems, as noted above and is especially troublesome to cattle ranchers in some geographical regions. Control of conjunctivitis is important to prevent long term damage to the animals and the value of the herd. Treatment of individual animals when each contracts the infection is expensive and very time consuming. Standard treatment often includes systemic injection of a wide variety of antibiotics, for example 3 milligrams of tetracycline per pound of body weight, and topical application to the eyes. Duration of therapy varies, but treatment normally extends for at least 2 to 3 days.
To reduce cost to the owner and damage to the animals susceptible to conjunctivitis, it is very desirable to provide a method of preventing or at least substantially reducing the likelihood of conjunctivitis in such animals, especially during the peak period for infection, and further to do so in a manner that allows a large group of animals to be treated simultaneously before start of the peak period, at a reasonable cost.